Our invention relates to a voltage indicating arrangement, and particularly to such an arrangement that provides an indication to the user of a radio transceiver that the supply voltage is low, and that also permits the radio transmitter to be operated for a short time duration.
In battery powered radio transceivers, such as handheld or personal radios, the battery which powers the transceiver may become discharged to a level where its low voltage may degrade normal voice transmissions. Or, even worse, the voltage level may drop to the point where the system voltage regulator becomes inoperable, with the result that the frequency of the radio transmitter may drift unacceptably. Frequently, the user of the radio transceiver is not aware of this condition, because the battery voltage may still be sufficient to enable the radio receiver to provide good reception, or to enable the radio transmitter to provide enough power to communicate.
In prior arrangements, there have been visual indications of a low transceiver battery voltage. In such arrangements, an indicator lamp may provide an intensity or may blink at a rate which is related to the voltage of the battery. However, the user may not notice the indicator lamp, or the indicator may be burned out. In such cases, the user will not be aware of the low battery voltage and resultant poor performance of the transceiver. Accordingly, there is a need for a reliable indicator that informs a user of the condition of the battery voltage, particularly for a radio transceiver.